Fionna and Cake
by Preci LV
Summary: Fionna tries to get Gumball's attention but Marshall Lee keeps getting in the way. Not realizing that he has secret feelings for Fionna, he asks Cake for her help, for he fears that she's falling for a trap.
1. Chapter 1

In the lovely land of Aaa, we see our two beautiful female heroines searching for any trouble and seeing if there was anyone needing any type of saving. Not willing to save their obnoxious snobby friend, Lumpy Space Prince, again, like they've did for the last few days, they decide to goof off for a bit while they have the chance, finally. Let me start off this beautifully written story with our favorite Ooo heroes as the beautiful and very crafty Fionna and Cake.

 _Adventure Time_

 _Come on, grab your friends_

 _We're going to a very distant land with Cake the Cat and Fionna the Human_

 _The fun will never end_

 _It's Adventure Time...!_

Our beautiful blonde heroine, who we like to call Fionna the Human, was graceful and tough for a girl who was sixteen years of age, despite her tomboy demeanor and knows definitely how to wield a sword while her pet cat, who she calls her big sister at twenty-five years of age, Cake the Cat, walks along with her little sister. Cake can stretch her body and also shapeshift into anything imaginable (the source of her powers are unknown, I think, so far). Not knowing who her parents were, Fionna was adopted by Cake's parents and they raised her as their own. Always looking down on Fionna and making her feel weak sometimes, her adopted mother took her and Cake under her wings and taught them how to fight crime while her father was always protective of the two girls.

Hoping that some type of danger would lurk, Fionna flings her sword around while she plays with her 90s style cell phone. Looking at her sister cautiously, she warns her sister not to twirl her sword like that or else she'll cut herself. Fionna was making her sister angrier by not listening to her (which was mostly her prerogative to aggravate her enemies and Cake, as well). Being a huge showoff, she twirls the sword, only to hit a tree branch and nearly landing on Cake. Fionna catches it, luckily and puts it in safely into her backpack. Glaring at Fionna, Cake growls under her breath and mumbles something that Fionna couldn't hear. All of a sudden, Fionna's cell phone rings. Fist-pumping in the air and shouting, "Finally!" at the top of her lungs, she happily answers the phone, but her smile quickly fades away as she answers it. It was Prince Gumball, her secret crush but she knew better than to like him, for he was royalty and was twenty-one years of age. She can imagine his face over the phone. His Mohawk-ish like reddish-orange hair and prince like attire. She quickly snaps out her daydream.

"Hey, Gumball. Wha-what's up?"

"Oh, hey Fionna. I was wondering if you could come over and test something for me. And bring Cake too, if you want."

Fionna was too quickly to get excited for Gumball's invitation only to get shot down that it wasn't like a date. Realizing her sister was still there, Fionna agrees to come to his castle alone and hangs up without saying goodbye accidently. She sighs a sad sigh and walks away, forgetting that Cake was still there. Catching up to her, Cake asks Fionna about their conversation. She tells her what happened but leaves out the part that he invites Cake as well, for she had secret plans to get Gumball's attention. Fionna heads out to see Prince Gumball in his castle, leaving Cake astray. Wondering what were her sister's intentions, she secretly follows her, for she knows that Gumballs always includes Cake in everything and hoped that Fionna wasn't being hung up on her secret crush that Fionna thinks that Cake didn't know but she did.


	2. Chapter 2

Fionna took the nearest train to Prince Gumball's castle. Jumping off of the moving train dangerously and landing on top of a tree branch with ease, she takes a look in Gumball's bedroom window. He was wearing his lab goggles and was testing something with electricity. Holding two large electrical wires with clips on them in his hands, he hooks them up on one side of someone's temples and runs over to a large machine and flips the switch. Seeing the body being shocked, Fionna nearly falls off the tree and watches with intrigue. She slowly taps on the window and waves at him as he looks at her. He waves back and quickly opens the window; Fionna falls inside his bedroom and screams out in pain. He helps her up and sets her on his bed. Fionna tells Gumball not to worry because it was just a sprained ankle. Gumball sighs a breath of relief and pats her back. Fionna blushes and nearly falls off the edge of his bed. Catching her arm, Gumball helps her up and sits her down, chuckling at her clumsiness. Fionna chuckles with him and asks about the project she wants her to test out. He points to a body that he had set on top of a table and it was looking like some type of Frankenstein creature, then he gives her two wires to connect to the monster.

 _It looks like that's he planning one of his mutations again. He's really smart for a pretty face. Stop it, Fionna and focus! Shake those thought outta your head right now before he notices..._

Gumball awakes Fionna from her beautiful Gumball daydreams as he wants her to attach the wires she has in her hands to the monster that he was creating. Plugging in the two wires to his head, Fionna nearly jumps back as Gumball flips the switch that activates the machine and shocks the monster. The monster rises up from the table. Fionna screams and hides behind Gumball, holding on to his hips. Gumball squirts the monster with water, making him calm down and sit on the table and behaving himself. Fionna lets go of Gumball slowly and blushes at her actions. Gumball takes off Fionna's bunny cap and her long blonde hair dangles to her elbows. Blushing, Fionna plays with her hair. Gumball puts one hand on Fionna's shoulder and the other hand on her cheek. Not realizing that Cake was secretly watching the both of them, she slowly shakes her head at her little sister and mumbles under breath.

 _Oh, my dear sister Fionna. You'll never understand that Gumball's too old for you. Fionna, will you ever get a grip...? I shouldn't judge her...she's just a teenager._

Just then, Cake feels a cold breeze. Shivering and looking around her surroundings, she nearly screams as she sees our favorite vampire bad boy, Marshall Lee AKA The Vampire King. Cake nearly slaps him for giving her a heart attack. Marshall Lee laughs at Cake and jokes around with the dear poor cat. She growls and jumps down from the tree branch for Fionna and Gumball nearly caught on to them. Cake demands Marshall Lee to tell her what he were his bad boy intentions this time. He replies that he wanted to see Fionna. Cake glares at him, for she knew that Marshall Lee was a playboy. But this time, Marshall wasn't messing around. He was serious. He wanted to tell Fionna how much he felt for her. Looking at Marshall with confusion, she asks him what made him want to tell Fionna this for so long. He says that he wanted to wait for the right moment. Cake reminds him that he was _way_ older than Fionna, for him being over a thousand years old. He says that it was true, but he was stuck at the age of sixteen. Cake growls as she knew that he was right. Marshall tells Cake that he doesn't think that Gumball was good for Fionna and that he was up to something. Cake wonders if he was saying that because he was jealous. Marshall growls at Cake then slowly calms down and huffs at the cat. Floating away, he tells Cake that he wanted to talk to Fionna. As he leaves, Fionna manages to find Cake and waves at her. The two sisters hug it out. Fionna asks Cake if that was Marshall Lee she just saw. Cake nods her head and tells her Marshall's message.


	3. Chapter 3

"What do you mean Marshall has feelings for me?", yells Fionna.

Fionna and Cake were inside their treehouse as they were still discussing about Marshall Lee's feeling for Fionna.

"Marshall Lee's a jerk! Why would he like me?!", she continues.

"That's what he said.", says Cake meekly.

"Maybe he's lying so he won't see me happy."

"Well...Gumball's a bit old for you..."

"I **know** that!"

"Do you? 'Cause it seems to be going in one ear and out the other!"

"Don't tell me what to do, Cake! It's my life and I do what I want with it!"

"Oh my grapes, Fionna. You're a brat, ya know? A. Brat."

"Not as much as you being a brat."

"Fionna, I'm not a bad guy here. I'm trying to get you to understand-"

"No. Shut up. I'm talking now." Cake raises one of eyebrows real sassy like. Did Fionna just do what we think she's doing to Cake? "I'm only sixteen and I'm capable to taking care of myself."

"Oh, yeah? You think you can take care of yourself?"

"I don't think. **I know!** "

"Wow. Okay. You can take of yourself."

"THANK you."

Cake was walking into the bedroom that they share and she was going through Fionna's dressers. She sees her sister going through her stuff and it was angering her. She grabs a hold of Cake's shoulder.

"Dude, what the heck are you doing?!"

"You said you can take care of yourself," she says as she puts Fionna's clothes into a suitcase, "so take care of yourself."

"You're kicking ME out?!"

"That's what you want, isn't it?"

Fionna couldn't believe this. Her own sister was kicking her out of the house and leaving her all by herself. Fionna, in her mind, thought that Cake was being selfish but Cake was being reasonable by showing Fionna responsibility. Fionna was crying now. But Cake wasn't falling for it. She was already done packing her stuff. All Fionna needed to do was to make up her mind. Should she stay or should she go...? Fionna looks at her sister with tears in her eyes, blurring up her vision. Cake had her paws on her hips as she stares back at her sister as she was waiting for her to make up her mind. Fionna breaths in and grabs her stuff in her suitcase.

"So this is it then. You're leaving."

"Yeah. Yeah, I am."

"Good luck finding someone dumb enough to let you in..."

Fionna was already out the door. Cake sits on Fionna's bed and weeps to herself.

 _I had to do it. It wasn't easy...but she'll learn one day. She'll be back. She'll be back._

Walking in the rain, Fionna searches for another place to stay. It wasn't easy. She didn't know anyone nor she had the guts to ask. Crying as she fell on her knees, she spotted a familiar cave and goes inside where she spots a blue and black colored house. She knocks on the door and a boy opens it. Smirking at him, she goes inside.

"You're wet."

"I know that."

He tosses a towel at her. She catches it and dries herself off. Taking off her bunny hat and hangs it up to dry, she stares at him, who had on a black t-shirt and ripped jeans. He stares back and smirks, showing his vampire teeth.

 _Marshall Lee's a butt...but he can help me out. Besides, I need to ask him a few questions._

"Marshall."

"Yes, my dear Fi-Fi?"

"Fi-Fi is a DOG'S name."

"I know."

"You're a butt."

"Thank you for checking it out."

"Dummy."

He sticks his tongue out. She laughs.

"Marshall? About...umm...Cake told me..."

"I know. I told her to."

"Why do you hate Gumball so badly?"

"It's not that I hate Gumball. I'm just looking out for you."

"Why?"

"I care?"

"Really."

"Really."

"I...love you, Fi."

Fionna eyes him with caution. She didn't trust him, but they were friends. They both like the same things and like to get under the other one's skin. She eyes him up and down.

"Why...?"

"I...don't know...but I do."

"Oh."

"What are you doing here anyway...?"

"Cake...kicked me out."

"What...?! Why?"

"We had a fight."

"Must be a big fight for her to kick you out."

"I don't care because I can take care of myself."

"You're only sixteen."

"You're sixteen too and look at YOU!"

"I'm different, Fionna and you know it."

"You're lucky I came to you."

"I actually thought you'd go to Gumball."

"Do you want me to?"

"No! I mean...naw."

"Naw?"

"Yeah, naw."

"Heh."

"What?"

"You're funny."

"Thanks. It's a gift."

Fionna smiles and felt glad that she came to Marshall Lee. Maybe...he wasn't bad. Fionna was suddenly coming close to Marshall. He didn't understand it, but she was hugging him. He finally found himself kissing her. Fixing her long blonde hair, he looks her in the eyes and kisses her again.

"Thank you, Marshall.", says Fionna as she cries upon his chest. Marshall couldn't find his voice. Eventually after a few minutes, he kisses her forehead and says, "I love you."

"I love you, too."


	4. Chapter 4

Fionna and Marshall Lee were walking around Aaa, pulling pranks and causing mischief. They fell to the ground laughing until Fionna eyes a pair of feet belonging to Prince Gumball. Scrambling to her feet quickly, she says hello to the prince and asks him what was he doing here. He replies to our heroine that he was taking a stroll around and asks her if she'd care to join him. She quickly agrees but remembers that Marshall was standing right there, so she declines sadly. Gumball tries to persuade her to come with him. Marshall chuckles under his breath and mumbles, "Poser."

Gumball walks up to the bad boy vampire and says, "I've heard that, dear Marshall. Don't be jealous. It's bad for your health."

"I'm already dead, dunce!"

"Exactly. Your death was caused by _jealousy_. Excuse me, Marshall, as me and Fionna have things to discuss... _mature people_ things...right, Fi?"

"Uh. I-uh...um. Sure, G-gumball."

"What?! Fionna, you're not gonna leave me for this **bozo** , are ya?!"

"Calm down, Marshall."

"No way!"

Fionna pulls Marshall to the side as she tries to calm him down and talk to him reasonably.

"Marshall, I'm going to be a minute, okay?"

"No. He's a crooked dude. He's...not himself. Fionna, if you love me, you'd stay away from him."

"Oh my grapes, you're acting like Cake!"

"Someone has to. I know you're independent. But...trust me."

"Should I _really_ trust you...? You're a deceiver, Marshall."

"You're in love with a deceiver."

"I hate you, Marshall Lee!"

"The same goes for me too."

Fionna's eyes were swelling up with tears. She tries to wipe them off herself, but Marshall beat her to it. She pushes his hands away from her face and leaves with Prince Gumball. Gumball wraps his arm around Fionna's neck as they walk off together but she didn't bother to notice Gumball turning his head and smirking at Marshall Lee. Marshall Lee growls and reveals his fangs but slowly tries to calm down. He wasn't going to let some pretty boy stuck-up snotty rich kid play him like that. He wanted to tell Cake what happened, but he remembered Fionna telling him their big fight. Cake might be still upset at Fionna for how she treated her. And Fionna might still be upset at Cake for kicking her out. But they're sisters. They were going to have to make up at some point.


	5. Chapter 5

Marshall Lee was floating in midair when he arrived to the treehouse. He slowly starts to remember the times when he used to live there, but shakes the thoughts out of his mind. Fionna was in trouble in his mind, but was she? Marshall knocks on the door. Cake opens it and was about to yell but quickly stops as she sees the vampire king. She growls and huffs.

"What do you want?"

"Fionna's with Gumball."

"Ok. And?"

"She's. With. Gumball! Do you care?"

"No. All I care...she can be with _you_!"

"She WAS with me. I took her in yesterday. Now, Gumball took her away from me. Something's not right with him, Cake. You gotta help me."

"Why the DONK would I help her?!"

"She's your sister."

"You shoulda been here yesterday, Lee."

"I know. She's sorry. She didn't know better. But, you shoulda been more understanding. You girls are sisters. That's a bond nobody can break. And you're letting Gumball get his way. That's what he wants. Cake, can you please help me rescue her? I love her. I mean...she's unique. We both like the same things. We get on each others' nerves. But, it makes me...feel...something. She understands me...you know...? And I understand her. Help me, Cake...please. I know you hate me and want nothing to do with me...but just...this one time. And I won't bother you two ever again."

Cake was having tears into her eyes. Her heart was feeling very heavy with pain and guilt. She had underestimated him after all. He really cared about her little sister. She wanted to help more than anyone. BMO came into the living room where they were at and told them that Fionna has been captured into Gumballs' castle. Marshall said that Fionna was supposed to be with Gumball. BMO replies, "She's been tied up _by_ Prince Gumball!"

"What?!"

"Gumball has my baby sister! That does it! Let's go, Vampire King!"

"Finally, some action around here!"

"I wanna come too!", says the overly-excited video game.

"No, baby. I'm sorry but you have to stay put."

"Awww! Please, Cake!"

"Ugh...fine. I don't trust you in the treehouse by yourself, anyways. Like the last time..."

"It was an accident."

"Setting the house on fire was no accident!"

"Hmmph.", says BMO with his arms folded. Marshall Lee carries the video game in his arms and says, "Let's go kick some prince butt!"

"And rescue my baby!", says Cake.

"Adventure Time!", says BMO.

The trio all ran out the door to save our favorite heroine from the clutches of...Prince Gumball...?


	6. Chapter 6

Marshall Lee kicks the entrance to the castle down. Several Banana Guards cam scattered around them. He bites one of the guards on the neck. Cake was punching them while wrapping their bodies with her stretchy arms. BMO was trying to karate chop them, but was so adorable doing it. One of the banana guards recognized Cake and apologized for their behavior. Cake apologized for Marshall Lee's kicking down of he door. Marshall was blushing and looking down at the ground. As the guards let them into the castle, they saw Lady Peppermint Butler. Marshall grabs the peppermint and asks her where was Fionna. She screams out that she didn't know what he was talking about.

"Don't lie to me! You know where she is!"

"Calm yourself, Lee!", cries BMO as he tries to make him let go of the butler. Cake sniffs the air and found Fionna's scent. She was walking towards her scent until she hears a shrill girl's scream.

"Cake! Cake, help! Someone help me!"

"Fionna? Don't worry, baby child! I'm coming!"

She was running now. Into Gumball's room. Where she found her baby sister tied up next to...Gumball?! That Gumball had his moth taped while Fionna was nearly crying with fear and happiness that her sister was here. Cake was really confused! For she saw the other Gumball with his evil smirking face. It didn't make any SENSE! How were there _two_ Prince Gumballs? Was it an experiment gone wrong? Cake was just standing still.

"Fionna...what's going on...?"

"I don't know! Help us, Cake! Please...I'm sorry..."

"I'm sorry too. Okay, Gumball...! How is...what is this...?"

The other Gumball punches Cake in the face. She rebounded and grabbed him by the hair and punched him back and bit him on the leg.

"Where-what are you?!"

"You stupid feline! It's me..."

The other Gumball took off his garments and revealed it was their nemesis...Ice Queen! Marshall was right. Gumball wasn't himself alright. Never did he realize it was a costume.

"Ice Queen, you butt," yells Fionna. "You messed with my emotions for the last dang time! Why do you hate us so bad?!"

"You're always around my dear darling Gumball. If I take you out of the picture and mess with you...maybe I'd crush your heart along with your spirit...", says Ice Queen as she crept inches closer to the sixteen year old tomboy. Pulling her bunny cap off of her hat, the Ice Queen tears it to shreds with her ice powers.

"You are a profound nut job, Ice Queen! You have completely lost it!", yells Gumball. Ice Queen smirks at the young prince and kisses him. "Oh, Gumball. You're such a dream boat!"

"Shut up, you old bag!", says Fionna. Ice Queen quickly grew angry at the young girl.

"Look. I'm growing very weary of you clowns. Time to die!"

Ice Queen uses her ice powers on Cake but was quickly dodging each ice bolt. Fionna was trying to cut the rope with piece of sharp ice. As she breaks free, she grabs her sword and frees Gumball and snatches the tape off of his mouth. Screaming, he was feeling his face. She blushes and mouths out an apology. They both smile at each other as they run to Cake's aide and goes into the fight. After defeating Ice Queen, Fionna takes her crown off of her head.

"You brat! That's how I get my powers!"

"You won't need your power where you headed! Guards!", says PG.

The banana guards came to take Ice Queen, who was smirking and laughing to herself, away. As they escort her away, Marshall Lee runs into the room with BMO in his arms. "Hey. I heard a commotion. Is everything..."

He stops in midsentence to see Prince Gumball, who was waving at him. He growls and starts attacking him. The girls were pulling him off of the young prince.

"Marshall, stop! It's the real Gumball!", says Fionna.

He stops and slowly looks at the prince. Smiling meekly, he gets off of him and apologizes.

"My bad, Gummy. Wait. I was right the whole time...? HA! Told ya he wasn't the real Gumball! No wonder he felt so different!"

"It was Ice Queen in disguise.", says Cake.

"Wow! Dah-dah-dah!", says BMO.

"Why is BMO here?", asks Fionna.

"Cause I can't trust BMO alone in the house by himself."

"It was an accident!", says BMO.

"Are we talking about the fire incident?"

"Yep, Fi."

"Oh yeah...that was funny."

"We were close to getting a new HOUSE!"

"BMO is BMO. He can't help himself."

"Yea! I can't help myself!", says BMO, running to Fionna's side. Cake growls and says, "Let's go home."

As they walk home, Fionna apologizes to Cake about yesterday. Cake apologizes as well and hugs her sister. We both cry in each others' arms. Marshall was standing there, looking at them while he smirks to himself.

"Thanks for your help, Marshall.", says Cake.

"Ain't a thing, Cake."

"Yeah. Thanks, Marshall.", says Fionna as she hugs him and kisses his lips. Cake drops her jaw and BMO was cheering. Cake was covering his eyes.

"C'mon, Cake. Lemme see."

"No. You're a kid. Kids ain't 'posed to see these things."

BMO and Cake were fussing at each other while Marshall and Fionna hold hands.

"C'mon, y'all. Let's go on home.", says Fionna.

"Are you and Marshall Lee a couple now?", asks BMO. Fionna and Marshall look at each other.

"Don't know. If Fionna can keep up."

"What you MEAN keep up?"

"Your baby attitude can't handle my intensity." Fionna pushes Marshall to the ground and tackles him. Cake says, "Alright, you two. Stop!" Fionna kisses him again and got off of him as they went home.

 **The End!**


End file.
